Bevel Problems, need assistance
First, check if using the bevel modifier by itself works. Make sure your scale is applied as well.
If the bevel does work, you will need to create a vertex group with all the top faces of the text selected. You can then use that vertex group as a mask for the bevel modifier.
If the bevel modifier doesn't work, let me know and we can sort something out.
EDIT:
I did some experimentation, and it turns out that the text object in Blender has a bevel option! Simply just edit the bevel settings the way you want, then convert the text to mesh. You can then delete the bottom section of the text, re-extrude downwards, and voila!

The screenshot above is from Blender 2.92, and I see you're using 2.82. Most of the options should still be there, but if they aren't...
Then you'll have to retopologize your text and then apply a bevel modifier on that.